Molecular Flashcards
1
Q
Stats
A
3 billion base pairs
22,000 Genes
1.5% encodes for genes
AT has 2 bonds
GC has 3 bonds
2
Q
Mutation types
A
Silent - not a problem because more than one codon codes for amino acid (redundant)
Missense - wrong amino acid called for, may or may not be a problem
Nonsense - premature stop codon
Insertion
Deletion
3
Q
Codons
A
All proteins start with AUG > Methionine
UAA, UAG, UGA are stop codons
5’ cap and poly A tail is added before leaving nucleus
4
Q
Inheritance
A
- Autosomal Dominant -
- often are neurologic, connective tissue (Seizures,Huntingtons, Marfans, Achondroplasia)
- vertical transmission
- Autosomal Recessive -
- often enzymes
- most common, usually no family history except horizontal
- cystic fibrosis, sickle cell disease, phenylketonuria.
- both parents are carriers
- X-linked Recessive
- No male to male transmission
- fabry dz, muscular dystrophy, hemophilia a/b, red-green color blindness
- X-linked Dominant
- very rare
- Rett syndrome, Incontinentia pigmenti
5
Q
Mitochondria Inheritance
A
- two to three symptoms with no connection think about mitochondrial
- circular dna
- 37 genes, all related to oxidative phophyrylation
- still uses many nuclear DNA for these pathways
- Maternal inheritance
- can have heteroplasia where some mitochondria have a mutation and others do not
- Examples
- Kearns Sayre, Leber Heriditary Optic Neuropathy, MELAS, MERRF
6
Q
Genomic Imprinting
A
- Only the mother or father’s gene is not expressed
- methyl groups prevent one from being transcribed
- sometimes need methylation studies to figure things out
- most of one of the X chromosome or inactivated in females
- Examples
- Angelman: UEB3A gene only active when inherited from mother
- Chromosome 15, deletion on 15q mutation can also lead to PW
- Prader Willi: SNP gene only active when inherited from the father (prader no father)
7
Q
Triple Repeat Disorders
A
- Autosomal Dominant
- Huntington Chorea : CAG coding exon
- Myotonic Dystrophy (DM1): CTG 3’ end
- SCA (Spinocerebellar ataxia)
- Autosomal recessive
- Friedrich Ataxia: GAA intron
- X-Linked
- Fragile X (expansion 5’, CGG, increased expression in oogenesis)
- often not identified in NGS but can be identified in whole genome studies
8
Q
Cell Cycle Review
A
- Checkpoints in the cell cycle
- Proper cell growth (G1)
- Is DNA replication correct? (G2)
- Mismatch repair
- May not pass, no more replication
- Cancer cells might skip checkpoints
- leads to uncontrolled proliferation
*
- leads to uncontrolled proliferation
9
Q
Blotting Techniques
A
- Southern (DNA)
- Northern (RNA)
- Western (Protein)
- Disadvantages
- needs lots of blood (no application)
- time consuming